Like nearly every entertainer who first experiences stardom in childhood, Demi Lovato and Nick Jonas are navigating the uncertain transition into adulthood.

Both were in their midteens when they appeared in the Disney Channel movie “Camp Rock” in 2008, Jonas as part of the boy-band trio the Jonas Brothers, who would evolve into an arena act before dissolving and going their separate ways in 2013. This year, he released “Last Year Was Complicated,” his third solo album and second since his band broke up.

Saturday night, the two performed at the Sprint Center, drawing a crowd that nearly filled the lower levels and floor of the arena (all the upper levels were closed). It’s a co-headlining tour and deftly executed as such. Their performances were woven together and on one co-performance, “Stone Cold,” Jonas accompanied on the piano.

Backed by a five-piece band performing from a pit at the back of the stage and two backup singers, he opened the show with “Levels,” a bright and catchy, soul-infused pop concoction that epitomizes the radio-ready sound he aims for these days. His long-legged singers, wearing only thigh-length, button-down shirts, joined him onstage, their attire making it clear that the themes for the evening would be aimed more at young adults than preteens and tweens.

Never miss a local story.

Sign up today for a free 30 day free trial of unlimited digital access.

The stage was equipped with a large, wide screen that projected an array of videos and visuals. During “Champagne Problems,” a breakup song, it showed foggy images of a barely clad woman. He followed that with “Good Thing,” a Sage the Gemini cover, then played guitar during “Who I Am,” an anthem about heartache and the need to be appreciated for who he really is.

He followed that with “The Difference,” then “Bacon,” a song filled with explicit sexual innuendos and references that were probably a little too PG-18 for some of the younger audience members.

After “Chains,” Lovato appeared onstage, transported on an enormous cube. She opened with “Confident,” the title track of her fifth studio album, released in October. Lovato has a powerful voice, one that easily fills an arena and recalls other brawny-voiced singers like Kelly Clarkson. She needs it to execute the hearty, skyscraping anthems and ballads she sings, like “Heart Attack,” “Neon Lights” and “For You.”

She initially stripped-down “Fix a Heart,” performing the beginning accompanied only by an acoustic guitar until the rest of the band jumped in toward the end. She followed that with “Nightingale,” a ballad with a vibe that recalls Bette Midler’s hit “The Rose.”

After Jonas joined her on “Stone Cold,” he took over again for a few songs, including “Chainsaw,” which includes the preposterous lyric: “I’ll take a chainsaw to the sofa / Where I held your body close for so long.” That’s what jealousy can do to a guy.

Lovato closed the show with a few more full-throated anthems, like “Skyscraper.” She ended with “Cool for the Summer,” a bright, bouncy pop song with sex on its mind: “Got my mind on your body / Got your body on my mind.”

Ultimately, the show lived up to its name, the Future Now Tour, because it had little to do with either one’s roots or distant past.